Energy/Heat Assisted Magnetic Recording (EAMR/HAMR) systems can potentially increase the areal density of information recorded magnetically on various media. For example, to achieve magnetic information storage levels beyond 1 terabit per inch squared, smaller grain size media may be required. Such designs can demand higher Ku materials for a magnetic recording layer to sustain thermal stability, such as L10 ordered FePt alloys.
The layer beneath the FePt magnetic recording layer (e.g., intermediate layer or underlayer) may be important to the media design to achieve the desired microstructure of the FePt magnetic recording layer. For example, one aspect controlling the FePt microstructure is the interfacial energy between the FePt magnetic recording layer and the intermediate layer, which varies depending on the segregant in the FePt magnetic recording layer and the intermediate layer properties. Recently, HAMR media including FePt magnetic recording layers has been optimized in terms of microstructure and magnetic properties using an MgO intermediate layer, together with a carbon segregant in the FePt magnetic recording layer.
However, when using intermediate layers other than MgO, carbon may not be an ideal segregant. For example, other intermediate layer materials may cause carbon to diffuse away from the intermediate layer interface, resulting in the formation of larger interconnected FePt grains. Accordingly, an improved HAMR media structure that addresses these shortcomings is needed.